Operation CHARM: Car repair manuals for everyone.

Anti-Lock Brake - Aftermarket Products Usage Precaution

Group Ref.: Brakes

Bulletin No.: 435001

Date: February, 1994

INFORMATION

SUBJECT:
AFTERMARKET ANTI-LOCK BRAKE SYSTEM PRODUCTS

MODELS:
1994 AND PRIOR PASSENGER CARS AND TRUCKS

The brake system is one of the most important features on any passenger vehicle.

Several products which tap into the master cylinder and/or brake system and claim to improve brake system performance are being sold in the aftermarket. Some of these products imply performance similar to new vehicle anti-lock brake systems.

However, contrary to their claims, add-on systems which deplete fluid from the master cylinder on brake apply may actually increase a vehicle's stopping distance. This may cause the vehicle to fail to comply with Federal Motor Vehicle Safety Standard (FMVSS) 105. If this happens, the facility which altered the vehicle could be liable for rendering the brake system "inoperative".

GM would like to remind each dealer of their legal obligation with regard to any actions which might take a vehicle out of compliance with FMVSS, and to stress the need to understand the operation of any aftermarket system offered to your customers.